[New-bugs-announce] [issue10125] Closing a file within its writelines method causes segfault
report at bugs.python.org
Sat Oct 16 19:00:21 CEST 2010
New submission from intuited <cecinemapasderange at gmail.com>:
Discovered when using the current Ubuntu 10.04 package of Python: 2.6.5-0ubuntu1
Reproducible with ::
outfile = open("tmpout", "w")
outfile.writelines(f() or "line" for f in (outfile.close,))
This problem is probably most likely to be encountered when using the ``fileinput`` module, because of the way it abstracts away the closing of files. E.G.::
from fileinput import input
lines = input("tmpout", inplace=1)
first = lines.next()
from sys import stdout
Both of the above pieces of code cause Segmentation Faults.
It looks like in line 1779 of ``Objects/fileobject.c``, ``f->fp`` is being passed to ``fwrite`` as 0. I guess this happens because no check is done after the call to ``PyIter_Next`` on line 1730 to see if the file is still open.
I don't see this as a big issue, though it is annoying that it seemingly prevents generators from being used with the `fileinput` module. Doing so would be a bit awkward and hacky anyway though.
title: Closing a file within its writelines method causes segfault
versions: Python 2.6
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